β-US2 with the orthorhombic structure is an interesting compound of which the electrical property is changed from a metallic state to an insulating state at temperatures lower than 80 K. To clarify the present metal-insulator change, we carried out the magnetization and magnetoresistance measurements in magnetic fields up to 50 T. The magentization at 4.2 K saturates above 40 T, reaching 1.75 μB/U at 50 T for the magnetic field along the magentic easy-axis, namely the  direction. The corresponding electrical resistivity at 4.2 K is steeply reduced in magnitude from 1 × 103 Ω·cm to 2 × 10-2 Ω·cm at 50 T only when the magnetic field is applied along the  direction. The temperature dependence of the electrical resistivity at 50 T indicates a usual metallic behaviour. The conduction electrons are most likely released from the trapped U-sites when the 5f-CEF magnetic moments are fully polarized in high magnetic field of 50 T. The present experimental results are discussed from the viewpoint of the magnetic polaron.
All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)